某高含硫气田开发过程中SO2排放对区域土壤影响的分析

高含硫气田开发过程中SO2排放会对区域生态环境造成一定的影响,以国内某大型气田开发工程为例,以净化厂为中心,布点采样及试验测定分析了该气田开发过程中SO2排放对土壤有效硫、pH以及有机质的影响,从而探讨其对该区域土壤的综合影响,为气田开发与土壤保护工作的开展提供了依据.结果表明,2010年10月土壤有效硫含量稍高于2009年10月;2010年10月土壤pH、有机质含量稍低于2009年10月.该气田开发过程中SO2排放对区域土壤的影响甚微.     

综合利用水库可供水量计算

以威海市泊于水库工程为例,根据流域现状工程条件下来水情况,按照供水任务的主次顺序,设定一定的限制库容,按照长系列时历法进行调节计算,得到水库的可供水量;同时为减少弃水、充分利用洪水资源,在满足供水任务各自保证率的前提下,按照不均匀供水进行优化长系列调算,得到更多的可供水量。并对计算结果做出分析。     

天全河流域土壤氮素的空间分布特征及其影响因素分析

【目的】研究天全河流域土壤氮素的空间分布特征及其影响因素。【方法】采用常规统计、地统计学和地理信息系统相结合的方法分析780个表层土壤(0～30cm)样点数据。【结果】该流域土壤全氮含量达(1.40±0.52)g/kg,碱解氮含量达(125.79±56.24)mg/kg。土壤全氮含量由高到低为水稻土>潮土>黄壤>紫色土,土壤有效氮含量则为水稻土>黄壤>潮土>紫色土。全氮和有效氮块金值/基台值分别为0.78～0.90和0.96～0.97,两种氮素空间变异均以指数模型最好。【结论】全氮和有效氮的空间分布均呈由西向东逐渐减少的趋势。成土母质、地形部位、土地利用和耕地种植制度都极显著地影响土壤全氮和有效氮的含量。     

基质在热带兰栽培过程中的养分释放研究

采用PT法探究几种常见热带兰栽培基质有效氮、磷、钾释放及pH变化情况。结果表明:整个试验阶段所有处理基质pH变化在5.24～6.88,适合大多数花卉生长,水苔受外界环境影响最大,有着较大的pH变化,不适宜热带兰长期栽培。各基质的养分释放并不是按一定规律来进行,混合基质养分释放量低于纯基质,混合基质可以避免纯基质养分释放量大的弊端。NH4+-N的释放遵循类似"U"型曲线变化,火山石与松树皮混合有利于NO3--N的释放。前60d内,A与B处理磷的释放变化较大,60d后磷含量表现为下降变化,直至趋于平缓,不过混合基质整体磷含量水平较低。A与B处理的钾释放量分别在第15和45天降至平缓释放水平,以后一直维持在该平缓水平上释放钾。     

藏北高原高寒草地土壤有效养分含量研究

选择藏北高原高寒草地不同海拔的12个样地对土壤有效养分进行研究,结果表明:在海拔4 480m优势植物为嵩草(Kobresiaspp)、苔草(Carex tristachya)的高山草原土速效氮含量较高;人工种植的在海拔4 530m的紫花苜蓿(Medicago sativa)和海拔4 300m燕麦草(Arrhenatherum elatius)有效磷含量较高;高山草原土壤速效钾含量较高;在海拔4 466m优势植物为早熟禾(Poasp.)的高山草原土有效铜和有效铁含量较高;在海拔4 481m高山草甸土的裸地有效锰含量较高;在海拔3 473m原生植被覆盖的亚高山草原土有效锌含量较高。有效氮、磷、铜、锌和锰在高山草原土中分布异质性较亚高山草原土、高山草甸土和高山荒漠土差;速效钾在各种类型土壤中分布异质性较均匀;有效铜在亚高山草原土中分布异质性较差。总体而言,藏北高原高寒草地中土壤有效养分含量高低和分布异质性,受到海拔高度、土壤质地、地上植被、人为开发利用及气候变化等多种因素影响。     

聚丙烯酰胺与强化剂联用对土-水界面磷素迁移的影响

采用静态吸附解吸试验结合模拟淹水试验,研究了聚丙烯酰胺(PAM)与四种化学强化剂(石灰石L,石膏G,沸石Z,腐殖质H)联用对土壤磷的吸持特性及土壤磷素向水体迁移释放的影响。吸附解吸试验结果表明:PAM和四种化学强化剂(添加量为5%)联用均能提高土壤固磷能力,磷平均解吸量和解吸率均小于对照(CK),其中以PAM+石灰石(P0.2+L)吸附能力最强,PAM+腐殖质(P0.2+H)次之;磷吸附动力学过程除PAM+石膏(P0.2+G)和P0.2+H符合抛物面扩散方程外,其余处理均符合Elovich方程和双常数方程。淹水试验结果表明:单施PAM时,0.1%PAM(P0.1)、0.2%PAM(P0.2)及0.4%PAM(P0.4)均可降低生物有效磷(BAP)的释放强度。当不同强化剂与PAM复合后,除P0.2+H外,其余均能有效抑制生物有效磷的释放,降低释放强度,其中以P0.2+L效果最好,上覆水体平均浓度和平均释放强度最低,分别为0.267 mgL-1和1.852 mgm-2d-1。干湿交替后,单施PAM抑制生物有效磷释放的效果明显降低,不同PAM施用量处理与对照无显著差异;而PAM与化学强化剂复合后,除P0.2+H外,其余处理均能持续抑制生物有效磷向水体的释放。     

南京江北地区菜地土壤有效态重金属的含量及空间分异特征

在南京市浦口和大厂的5大主要功能区（工业区、交通干线、居民区、蔬菜生产基地和风景区）内共采集了75个菜地表层土壤样品,以Cd、Cu、Pb和Zn等典型污染重金属的有效态含量为基础,运用经典统计分析、主成分分析和地统计分析相结合的方法对菜地土壤重金属污染进行了评估。结果表明,菜地有效态Cd、Cu、Pb和Zn的平均含量以交通干线沿线（宁六公路泰山新村-南信大段）最低,工业区（南钢或扬子石化）最高,其他功能区的均介于两者之间。主成分分析将菜地土壤有效态重金属大致分为农业源和工业、生活源。从功能区菜地土壤污染总得分排序结果可以看出,宁六公路沿线（泰山新村-南信大段）菜地土壤环境质量最高,以下依次是龙王山风景区、盘城蔬菜基地和盘城镇,老工业区的扬子石化和南钢周边菜地土壤环境质量较差。研究区内菜地土壤有效态Cd、Cu、Pb和Zn的空间分布均具有中等强度空间相关性,不同有效态重金属在空间上具有明显的各向异性,其空间变异主要发生在北-南方向。有效态Pb的空间分布较离散,有效Cd、Cu和Zn的高值区大致都位于老工业区内。     

不同取样尺度农田土壤速效养分空间变异特征初步研究

以3种取样间距(100m、50m、25m)进行网格取样,对土壤速效养分的空间变异性进行研究。结果表明:取样间距对土壤速效养分的含量水平、变异系数影响不显著;取样间距对合理取样数目具有一定的影响,合理取样数目分别为:碱解氮(71)、速效磷(36)、速效钾(18)。土壤速效养分的空间变异性主要受结构因素影响,但碱解氮与速效磷受随机因素影响强于速效钾。利用Kriging内插法绘制了不同取样间距土壤速效养分的等值线图。     

Development of an express method for measuring soil nitrate,phosphate, potassium,and pH for future in-field application

Background

In practical farming, there is often a need for short-term availability of information on the soil nutrient status.

Aims

To develop a new express method for the extraction of major plant-available nutrients and measurement of soil nutrients. In future, this method shall serve for in-field measurements of soil samples with an ion-sensitive field-effect transistor (ISFET).

Methods

Various extraction conditions such as type of extractant, soil-to-solution ratio, time, and intensity were investigated on a broad selection of dried soil samples in the laboratory. Based on 83 field-moist soil samples with varying clay contents, these conditions were compared to standard laboratory methods.

Results

With increasing extraction time, the nutrient concentrations increased. When the soil-to-solution ratio was reduced, a greater share of nutrients was extracted, independent of soil type. H₂O and 0.01 M CaCl₂ and standard calcium-acetate-lactate (CAL) solution proved to be too weak in the short period to reach the ISFET sensor measurement range. Higher concentrated CAL solutions performed much better. Finally, a 5-min CaCl₂ extraction followed by the removal of an aliquot for the determination of soil pH and NO₃⁻ was found to be effective. The remaining solution was then mixed with 0.20 M CAL solution for the analysis of H₂PO₄⁻ and K⁺ at 10 min of extra extraction time. This extraction method showed very good correlations with the values based on the German laboratory reference methods for pH (R² = 0.91) and for nitrate (R² = 0.95). For phosphorus and potassium, we obtained an R² of 0.70 and 0.81, respectively, for all soils. When soils were grouped according to clay content higher correlations were found.

Conclusions

A new express method based on a wet-chemical approach with a soil preparation procedure was successfully developed and validated. This seems to be a valuable basis for future in-field measurements via ISFET.     

Particle arrangement and internal porosity of coarse fragments affect water retention in stony soils

Information about water retention in stony soils lags behind due to methodological difficulties. We applied a new strategy to measure the water retention in soils with coarse fragments (CFs) and to get insights into the effect of CFs porosity on water retention. Water retention at zero, 10, and 150 m suction, bulk density, and the mass fraction of six particle size classes were measured in undisturbed blocks from soils with variable CFs contents, originating from three parent materials. The results showed that some soils contain porous CFs (2–250 mm) with a water holding capacity as high as the fine fraction (<2 mm). The water held in the suction range of 1–150 m in a soil with porous CFs was twice as high as in soils with non-porous CFs. Multilinear regressions revealed that both the water retention capacity at 1 m suction and in the range 1–150 m were more dependent on bulk density than on the fraction of CFs and fine particles. In the soil with porous CFs, there was no correlation between their fraction and soil water retention. These results show that the bulk water retention capacity of soils with CFs is underestimated when not considering the internal porosity of the CFs. A better understanding of the effect of the porosity of CFs on bulk soil porosity and water retention is important to propose suitable pedotransfer functions and refine physically-based hydraulic functions for stony soils.